This invention relates to compressors of the rotary vane type, and more particularly to improvements in a lubricating mechanism for rotary vane type compressors.
Generally a compressor of the rotary vane type comprises a rotor formed with a plurality of vane slots arranged radially for receiving therein vanes for movement in and out of the vane slots. As the rotor rotates within a cam cylinder, the vanes move radially in the respective vane slots in sliding reciprocatory movement to maintain the forward ends of the vanes in sliding contact with an inner peripheral surface of the cam cylinder at all times.
By the aforesaid arrangement, compression working chambers defined by an outer peripheral surface of the rotor, the inner peripheral surface of the cam cylinder, end plates sealing axial end portions of the cam cylinder and the vanes have their volumes varied as the rotor rotates, so that a fluid can be compressed and discharged by utilizing the difference in the volume of each compression working chamber.
Generally the rotor of a compressor of the type described is constructed by one of the two following processes: a rotary shaft and a rotor body are formed integrally of a ferrous material by machining or the rotary shaft and the rotor body are formed of a ferrous material as two separate entities by machining and made into a unitary structure by force fitting the former into the latter.
The rotor is formed with a plurality of vane slots arranged radially about the rotary shaft extending through the center of the rotor and located equidistantly from one another each for receiving therein one of the vanes for sliding reciprocatory movement.
An annular groove is formed at each of opposite ends of the rotor in a position in which the lower ends of the vane slots are located for maintaining the vane slots in communication with one another at their lower ends.
One of the end plates sealing the axial end portions of the cam cylinder is formed with oil passages communicating with a high pressure chamber formed on a side of the end plate opposite the side thereof on which the cam cylinder is located for supplying oil under high pressure to the annular grooves.
The oil fed into the annular grooves fills the bottom portions of the vane slots to apply a predetermined pressure to the lower end faces of the vanes in the vane slots.
The oil flows radially outwardly from the bottom portions of the vane slots and passes through a clearance between each vane and an inner wall of each vane slot to lubricate same, before flowing into the working chambers.
Heretofore, lubrication of the vanes and the inner wall surfaces of the vane slots has been effected only by the oil fed through the annular grooves on opposite ends of the rotor. Thus, rotary vane compressors of the prior art have had the disadvantage that when the pressure of the oil is low or its volume is small it is impossible to effect satisfactory lubrication of these parts.